1. Field of the Disclosure
The present disclosure relates generally to the field of to bone fixation systems, components thereof, and methods of implant placement used to adjust, align and maintain the spatial relationship(s) of adjacent bones or bony fragments after surgical reconstruction of skeletal segments. More particularly, the present disclosure is related in one exemplary aspect to devices that fixate the spinous processes at one vertebral level with the spinous process of another vertebra.
2. Description of Related Technology
Whether from degenerative disease, traumatic disruption, infection or neoplastic invasion, alteration in the anatomical relationships between the spinal vertebras can cause significant pain, deformity and disability. Spinal disease is a major health problem in the industrialized world and the surgical treatment of spinal pathology is an evolving discipline. The traditional surgical treatment of abnormal vertebral motion is the complete immobilization and bony fusion of the involved spinal segment and an extensive array of surgical techniques and implantable devices have been formulated to accomplish the treatment objective.
Vertebral fusion may be accomplished by using an anterior, lateral or posterior approach and each has particular advantages and draw backs. Frequently, circumferential fusion of the unstable level with fixation of both the anterior and posterior aspect of the spine is desired. This requires that patients undergo a combination of the aforementioned approaches. The anterior or lateral approaches are used to insert the bone graft and load bearing implants into the disc space between the adjacent vertebras while the posterior approach is used to place bone screws or similar fasteners that are used to immobilize the vertebral bodies.
Current implants to fuse the intervertebral disc space are usually comprised of an external superstructure that is capable of bearing the load transmitted across the implanted intervertebral disc space. An internal cavity is used to house and contain bone graft or bone graft substitute (collectively referred to as bone graft material) wherein the bone graft material is in contact with a bony surface of each of the vertebral bones that border the implanted disc space (i.e., the vertebral bones above and below the implant disc space). These devices are known in the art, see e.g. U.S. Pat. Nos. RE37,479; 4,820,305; 5,609,637; 5,749,916; 5,865,848; 5,888,224; 5,980,522; 6,071,310; 6,086,613; 6,159,244; 6,176,882; 6,206,922; 6,471,724; 6,582,431; 6,616,695, each of the foregoing being incorporated herein by reference in its entirety.
Given the large number of operative approaches and the substantial anatomical variation between vertebral levels within the same individual or across different individuals, the intervertebral disc implants must be manufactured and provided to the surgeon in a large range of sizes and configurations. This mandates that a large number of different sizes must be made and inventoried—adding to cost for manufacturer, vendor, and end user (hospitals). More importantly, the pre-manufactured devices may provide a suboptimal fit, since the surgeon must choose at the time of implantation from a series of pre-manufactured sizes and configurations that may not fit each and every patient.